Finite Element Analysis Of Military Off-road Vehicle Body During Airdrop Landing

This paper takes the development of heavy equipment airdrop technology as the research background,and uses the self-created finite element model of the military off-road vehicle body as the research object.Combined with the explicit dynamics analysis method,from the three perspectives of landing speed,landing angle and landing ground geological attribute,the car body model was analyzed by finite element analysis of 22 complicated working conditions,and three factors were summarized for the airdrop of the off-road vehicle body.The characteristics of the impact of the landing process provide suggestions for the actual vehicle airdrop landing process.At the same time,it proposes an improvement plan for the easily damaged parts of the car body to reduce the damage degree of the vehicle after airdrop landing and improve the use efficiency.The main research contents of the thesis are as follows:(1)Create a three-dimensional model of the military off-road vehicle body according to the selected model.From the aspects of finite element meshing,material property definition,boundary condition constraints and load settings,the airdrop working conditions of the vehicle body model are set to obtain the military off-road vehicle body-ground finite element model.(2)The ground model is first set as a rigid body,and the rigid ground landing is used for the extreme conditions,combined with the impact and collision evaluation standards and the actual vehicle test data,to verify the validity of the car body finite element model.By changing the landing speed(6m/s,8m/s,10m/s)and the landing angle(0°,10°,20°),9 simulations of the vehicle body landing on rigid ground were carried out,combined with the actual situation,The following suggestions are put forward for the speed and angle control of the vehicle body during landing:the vehicle body is airdropped and landed on rigid ground,the vertical speed should be controlled within 10 m/s,and the landing angle should be controlled within 10°.(3)Using the Drucker-Prager and Mohr-Coulomb constitutive models,finite element models of sand and mud surfaces were created,and 6 airdrop landing simulations were carried out(excluding the working condition with a landing angle of 20°).The simulation data of the vehicle body landing on three types of ground at the same speed and the same angle are compared,and the influence of the three ground geological attributes on the airdrop landing of the off-road vehicle body is analyzed:the muddy soil has the best buffer effect against the vehicle body landing process,Sandy ground is the second,and rigid ground has the worst buffer effect.(4)Based on the simulation results of all working conditions,the part that is prone to damage to the car body during the airdrop landing process is found,and the structure,size and material of the part is improved,from the three aspects of equivalent stress,equivalent strain and center-of-mass acceleration considering the improvement plan to ensure that the improved component meets the requirements of the vehicle body for airdrop landing.